- Add agent/stop_protocol.py with hard pre-tool-check gate
- Detect explicit stop/halt commands in last user message
- STOP_ACK logging to ~/.hermes/burn-logs/allegro.log
- Hands-off registry with 24-hour expiry in allegro-cycle-state.json
- Integrate gate into _execute_tool_calls in run_agent.py (fail-open)
- Add 33 compliance tests in tests/agent/test_stop_protocol.py